The present invention relates to an air-driven diaphragm-type process pump for transferring various fluids, e.g. chemicals, paints, and beverages.
In a conventional diaphragm-type double-acting process pump, diaphragms are connected together by being clamped to both the left and right sides of a center plate (body) by pump bodies, and a suction-side plate and a discharge-side plate are connected to the upper and lower ends, respectively, of the connected diaphragm assembly. Spaces formed between the center plate and the diaphragms on both sides thereof are defined as driving chambers, and spaces formed between the diaphragms and the pump bodies are defined as pump chambers. Inlet- and discharge-side check valves are provided in the upper and lower end portions of the pump bodies. A suction opening and the pump chambers are communicated through the inlet-side check valves, and a discharge opening and the pump chambers are communicated through the discharge-side check valves (for example, see Japanese Utility Model Application Post-Examination Publication No. 6-29503).
In the conventional process pump, the constituent members are assembled together from four directions, i.e. from the left, right, upper and lower sides of the center plate. Therefore, it is necessary to effect positioning (alignment) during the assembly operation, and hermetic sealing is required at the four joints of the assembly. To inspect or replace the check valves, it is necessary to detach the suction-side plate and the discharge-side plate from the upper and lower ends of the connected diaphragm assembly. To inspect or replace the diaphragms, it is necessary to detach not only the suction- and discharge-side plates but also the pump bodies, which are provided on the left and right sides of the center plate.